Three-phase biofluidization

This section of the current chapter goes beyond a simple listing of current three-phase biofluidization applications to consider the differences in conventional three-phase fluidization and biofluidization from the aspect of reactor design and operation. Past research into three-phase biofluidization has been summarized in several excellent reviews (Andrews, 1988 Fan, 1989 Heijnen et al., 1989 Schiigerl, 1989 Siegel and Robinson, 1992), and this chapter will concentrate on the main research themes and advances of the last few years. Though gas continuous three-phase fluidized bioreactors exist (Fan, 1989), we consider here only those bioreactors in which the liquid phase is the continuous phase. 

Table 14a. Recent Three-Phase Biofluidization Research on Treatment of Municipal Wastewater...

Several areas are receiving much of the research attention. Approaches that integrate product recovery with the fermentation in a three-phase fluidized bed bioreactor reflect general research trends in biochemical engineering (Yabannavar and Wang, 1991 Davison and Thompson, 1992). The successful use of three-phase biofluidization has also been demonstrated for recombinant protein systems, where it may have some benefit in improving plasmid stability (Shu and Yang, 1996). 

Table 15. Recent Applications of Three-Phase Biofluidization to Fermentation Processes...

Mass transfer considerations are critical in any bioprocess. In typical, aerobic, suspended cell fermentations, the major concern is the oxygen transfer rate, determined by the overall mass transfer coefficient, kft, and the driving force. In three-phase biofluidization, in which the cells are immobilized as a biofilm or within carrier particles, the situation is further complicated by possible intraparticle diffusion limitations. Numerous recent studies have addressed these issues. 

Table 20. Recently Developed Three-Phase Biofluidization Models...

Schugerl K. Three-phase-biofluidization—application of three-phase fluidization in the biotechnology—a review. Chem. Eng. Sci. 1997 52 3661-3668. 

HPLC Separation of Histamine. There are three possibilities for separation of histamine by HPLC normal phase on silica, reversed phase on a bonded silica column, or an ion-exchange separation. Perini (16) demonstrated that a cation-exchange separation is possible, but the analysis time was lengthy for examination of histamine in animal biofluids (70 min). Histamine is freely soluble in water, is slightly soluble in hot chloroform, and is insoluble in less polar solvents, making a... 

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